Cathode ray tubes having row and column electrodes attached to opposite sides of insulating substrate

ABSTRACT

In a cathode ray tube wherein an electron beam emitted from a cathode electrode is focused by an electron lens and deflected by a deflecting device upon a flourescent screen, a character forming means is provided across the path of the electron beam comprising an insulating substrate and electrode elements formed on the opposite sides of the substrate which are arranged in a matrix. The substrate and electrode elements are formed with aligned perforations at respective cross points of the matrix and the perforations of the electrode elements at selected cross points are caused to create positive field to permit passage of the electron beam to display a selected character, numeral or pattern.

Unite States Patent Nakamura 1 June 27, 1972 [54] CATHODE RAY TUBES HAVING ROW 2,965,801 12/1960 Archer et a1 ..313/86 X AND COLUMN ELECTRODES 3,198,976 8/1965 Starr ..3l3/86 KM ATTACHED TO OPPOSITE SIDES OF P Ex R be S a1 TR rzmary ammer- 0 eg KNSULATENG SUBS TE Attorney-Chittick, Pfund, Birch, Samuels & Gauthier [72] Inventor: Tadashi Nakamura, Ise, Japan [73] Assignee: Ise Electronics Corporation, lse, [57] ABSTRACT Japan In a cathode ray tube wherein an electron beam emitted from [22] Filed: Oct 8 1969 a cathode electrode 1 is focused by an electron lens and deflected by a deflecting device upon a flourescent screen, a p 864,798 character forming means is provided across the path of the electron beam comprising an insulating substrate and elec- 30 F i A i i p i i D trode elements formed on the opposite sides of the substrate 12 l 68 43 73904 which are arranged in a matrix. The substrate and electrode 9 Japan elements are formed with aligned perforations at respective 52] U 8 Cl 313/86 313/78 313/109 5 cross points of the matrix and the perforations of the electrode [51 1 3 29/06 3 U 29/7'4 elements at selected cross points are caused to create positive 58 Field 05551;. ..3l3/78, 86 field Permit Passage the electron beam to display a selected character, numeral or pattern.

[5 6] References Cited 1 Claim 7 Drawing Figures UNITED STATES PATENTS McNaney ..3l3/86 X PATENTEDauner I972 57 FIG. I 5

FIG. 3

I *1 *1 'l '1 I {I II INVENTOR TADASHI NAKAMURA BY W, WM, RMLL M 2 Mw a ATTORNEY CATIIODE RAY TUBES HAVING ROW AND COLUMN ELECTRODES ATTACHED TO OPPOSITE SIDES OF INSULATING SUBSTRATE BACKGROUND OF THE INVENTION However, as these prior cathode ray tubes utilize deflecting electrodes for selecting characters strict accuracies are required to fabricate electron guns thus rendering very difficult to manufacture them.

SUMMARY OF THE INVENTION It is an object of this invention to provide a novel cathode ray tube wherein it is possible to readily display the desired character with the desired size on the desired position of the fluorescent screen.

Another object of this invention is to provide a novel cathode ray tube which can display any selected character, numeral or pattern with a character forming device of simple construction.

According to this invention, in a cathode ray tube wherein an electron beam emitted from a cathode electrode is focused by an electron lens and deflected by a deflecting device upon a fluorescent screen there is provided a character forming device across the path of the electron beam. The character forming means comprises an insulating substrate and electrode elements formed on the opposite sides of the substrate. The substrate and electrode elements are provided with aligned perforations at respective cross points of the matrix and the perforations of the electrode elements at selected cross points of the matrix are caused to create positive field to permit passage of the electron beam to display a selected character, numeral or pattern on the fluorescent screen.

BRIEF DESCRIPTION OF THE DRAWING In theaccompanying drawing FIG. I is a diagrammatic longitudinal sectional cathode ray tube embodying this invention;

FIG. 2 is a plan viewof a character substrate comprising means for forming characters or patterns;

FIG. 3 is a diagram to explain the principle of forming a character according to this invention; I

FIG. 4 is a plan view of thefirst electrode provided on the character substrate;

FIG. 5 shows a section of one electrode element taken along a line V V in FIG. 4;

FIG. 6 is a plan view of the second electrode provided on the character substrate and FIG. 7 is a side view of the character substrate.

view of a DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the accompanying drawing, FIG. I illustrates a cathode ray tube embodying this invention and comprising an evacuated envelope I having a fluorescent display surface or screen 2, a neck surrounded by a focusing coil 3 and a deflection coil 4 which comprise an electron lens system, a cathode electrode 5 of an electron gun, a grid electrode 6 in the form of a mesh for uniformly dispersing electrons emitted from the cathode electrode 5, a character forming means 7 embodying this invention and an accelerating electrode 8. According to this invention, when passing through the character substrate the electron current emitted from the grid electrode 6 is converted into an electron beam which functions to form the desiredcharactor. After passing through the electron lens system shown as the deflection coil 3, the electron beam is focused on the desired position on the fluorescent screen 2 by the action of the deflection coil 4 thus displaying the desired character.

The character forming means 7 comprising the essential pom'on of this invention includes a character substrate 9 and matrix electrodes. As shown in FIG. 2 substrate 9 is made of a relatively thin plate of insulating material such as mica or ceramic. As shown, the substrate 9 is provided with a plurality of small perforations 10 arranged in a regular matrix. The substrate 9 provided with a plurality of perforations 10 is disposed at right angles to the axis of the neck of the envelope 1 to pass electrons from the grid electrode 6. In accordance with this inyention, passage'of the electrons through perforations 10 is selectively controlled according to the construction of the character so that electrons themselves which have passed through perforations form the electron beam which displays the character.

Control of the passage of the electron beam will now be considered with reference to FIG. 3, in which it is assumed that cross points between rows Y Y Y and columns X X X represent the positions of perforations 10 of the sub strate 9 shown in FIG. 10. Since these rows and columns comprise a matrix, it is possible to display any desired character, numeral or pattern by suitably selecting cross points. Thus, for example, in order to display a numeral 2, cross points between a and 4 5; 4 and 3 e; 5 and 6; 6 and 5; 1 and a X and Y and X through X,, are selected. Thus, by causing the electron beam to pass only through perforations 10 of the substrate 9 corresponding to selected cross points shown in FIG. 3 the electron beam entering into the electron lens system displays a letter 2. To provide such control of the passage of the electron beam cross points corresponding to the character to be displayed are selected, positive electric field is created at said selected cross points whereas negative electric field is created at the remaining cross points so as to permit the electrons to freely pass through selected cross points or perforations 10 that form the character to be displayed.

In accordance with this invention, the positive and negative fields are selectively applied to the perforations of the substrate by the matrix electrode; FIG. 4 shows the construction and arrangement'of thefirst electrode comprising the matrix electrode. The first electrode is comprised by electrode elements 11 of the same configuration each of the electrode elements 11 being provided with openings 12 of the same spacing as that of perforations 10 of the substrate (see FIG. 5). These electrode elements 11 are secured to one surface of the character substrate 9 and equally spaced from each other, with their openings 12 aligned with the perforations 10 of the substrate. Thus, electrode elements 11 shown in FIG. 4 may be termed as the row electrode elements because they correspond to rows Y Y shown in FIG. 3.

FIG. 6 shows the construction and arrangement of the second electrode secured to the other surface of the substrate 9. Like the electrode elements 11 of the first electrode, the electrode elements 13 of the second electrode have openings 14 aligned with the perforations 10 of substrate 9. Thus, electrode elements 13 have the same configuration as electrode elements 11 but are disposed at right angles to electrode elements 13, so as to correspond to the columns X,, X in FIG. 3 and may be designated as the column electrode elements.

As shown in FIG. 7, electrode elements 11 and 13 are secured to the opposite sides and are disposed at right angles with respect to each other, thus forming a matrix electrode. Since electrode elements 1] correspond to rows Y Y and electrode elements 13 to columns X X to obtain an electron beam that forms a desired character, electrode elements 13 (or 1 l) are successively scanned with a positive voltage while at the same time electrode elements 11 (or 13) are supplied with a positive voltage corresponding to the particular character so as to create positive field around the particular cross points or openings 12 and 14 comprising said character and negative field around remaining openings. Since the electron beam passes only through openings creating positive field, the beam that has passed through the character forming means functions to depict the selected character.

While in the above described embodiment, the row and column electrode elements are shown as being directly secured on the surface of the substrate it should be understood that this invention is not limited to this particular construction. For example, electrode elements may be formed by first providing electroconductive films on the substrate and then photoetching these films by any well known technique. Further, although for the purpose of description the spacings between perforations of the substrate 9 and between openings 12 and 14 are shown exaggerated, it should be understood that they are very closely spaced in the actual construction and that the smaller is the spacing the higher is the resolution of the character displayed on the screen,

Thus, according to this invention, a character beam forming means which forms a character by the selected cross points of a matrix is provided in front of a cathode electrode to change an electron beam entering into an electron lens system into a character information. For this reason, the focusing position of the beam and the size of the character displayed can be varied at will by the action of a deflection coil. Furthermore it is possible to simultaneously display a number of characters by forming a number of different character beams by said character forming means. In addition, the present invention is characterized in that it can display any character, numeral or pattern by the selective excitation of electrode elements com prising the matrix. When all electrode elements comprising the matrix are maintained at the same potential it is possible to use the cathode ray tube embodying this invention for conventional applications.

What is claimed is:

l. A cathode ray tube comprising a cathode electrode for emitting an electron beam, an electron lens means for focusing said electron beam, a deflecting means, and a character forming means disposed across the path of said electron beam, said character forming means including an electron impervious insulating substrate, and electrode elements in the fonn of separate rows and columns formed on the opposite sides of said substrate which are arranged in a matrix, said electrode elements and said substrate being provided with aligned electron permeable perforations at respective cross points of said matrix,

said electrode elements on one side of said substrate forming a conductive annulus around each perforation in said substrate with all of the annuli on said one side which are aligned in each row of said matrix connected only to a respective row conductor, and said electrode elements on the other side of said substrate forming a conductive annulus around each perforation in said substrate with all of the annuli on said other side which are aligned in each column of said matrix connected only to a respective column conductor, the set of respective row conductors being individually energizable to control the potential of said annuli on said one side selectively row by row and the set of respective column conductors being individually energizable to control the potential of said annuli on said other side selectively column by column, and the annuli on opposite sides of said substrate aligned with any given perforation being conductively isolated from each other but cooperating when simultaneously energized to create positive field at elected cross points of said matrix to form a desired character, numeral or pattern.

a r at k 

1. A cathode ray tube comprising a cathode electrode for emitting an electron beam, an electron lens means for focusing said electron beam, a deflecting means, and a character forming means disposed across the path of said electron beam, said character forming means including an electron impervious insulating substrate, and electrode elements in the form of separate rows and columns formed on the opposite sides of said substrate which are arranged in a matrix, said electrode elements and said substrate being provided with aligned electron permeable perforations at respective cross points of said matrix, said electrode elements on one side of said substrate forming a conductive annulus around each perforation in said substrate with all of the annuli on said one side which are aligned in each row of said matrix connected only to a respective row conductor, and said electrode elements on the other side of said substrate forminG a conductive annulus around each perforation in said substrate with all of the annuli on said other side which are aligned in each column of said matrix connected only to a respective column conductor, the set of respective row conductors being individually energizable to control the potential of said annuli on said one side selectively row by row and the set of respective column conductors being individually energizable to control the potential of said annuli on said other side selectively column by column, and the annuli on opposite sides of said substrate aligned with any given perforation being conductively isolated from each other but cooperating when simultaneously energized to create positive field at elected cross points of said matrix to form a desired character, numeral or pattern. 